CN203377950U - Digital meteorological facsimile machine - Google Patents
Digital meteorological facsimile machine Download PDFInfo
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- CN203377950U CN203377950U CN201320441947.7U CN201320441947U CN203377950U CN 203377950 U CN203377950 U CN 203377950U CN 201320441947 U CN201320441947 U CN 201320441947U CN 203377950 U CN203377950 U CN 203377950U
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Abstract
The utility model relates to a digital meteorological facsimile machine used for receiving meteorological information. The digital meteorological facsimile machine includes a radio frequency front-end module, a digital signal processing module and a display control module, wherein the radio frequency front-end module is used for completing the conversion from radio frequency signals to intermediate frequency signals, the digital signal processing module is used for completing digital demodulation of the intermediate frequency signals, and the display control module is used for displaying received meteorological facsimile charts and input control. According to the digital meteorological facsimile machine of the utility model, digital demodulation technology is adopted to convert received meteorological information into digital signals, and the digital signals are stored and displayed. The digital meteorological facsimile machine is advantageous in high precision, strong anti-interference ability and low cost.
Description
Technical field
The utility model relates to the marine communication device, specifically a kind of digital meteorology facsimile machine.
Background technology
According to International Meteorological Organization (WMO) regulation, weather facsimile radio broadcasting net has all been set up in each large zone in the world, to send the weather information of various places.According to weather information, boats and ships can obtain a large amount of useful maritime meteorology information such as marine weather distribution situation, weather forecast and alarm in time, this for ensureing navigation safety at sea, select the aspect such as best weather navigation significant.
Weather map facsimile equipment is for receiving the device of weather information.Up to now, China's H/HQC001 and ZSQ-3 type ship of development and production voluntarily mainly adopts analogue technique with weather map facsimile equipment, and bulky, precision is low, and poor anti jamming capability, to such an extent as to this product is not promoted at home.At present, the FAX-708 type weather map facsimile equipment of the FAX-408 that the major product in domestic boats and ships admittance market is Japanese Gu Ye company and Japanese ocean company, this two product is all to adopt analog demodulation mode type, and use traditional thermal printer to export meteorological chart, not only thermal head is easier to loss, and consuming a large amount of heat-sensitive papers, the working service cost is high, also is unfavorable for permanent preservation.
The utility model content
The utility model, for the problems referred to above, provides the digital meteorology facsimile machine that a kind of working service cost is low, precision is high.
According to the technical solution of the utility model: a kind of digital meteorology facsimile machine, comprise RF front-end module, digital signal processing module and display control module, described RF front-end module has been used for the transformation of radiofrequency signal to intermediate-freuqncy signal, described digital signal processing module has been used for the digital demodulation of intermediate-freuqncy signal, and described display control module is for showing weather facsimile figure and the input control of reception.
Described RF front-end module comprises connected successively low noise amplifier, tunable preselection filter group, variable gain amplifier, the first frequency mixer, the first intermediate-frequency filter, the first intermediate frequency amplifier, the second frequency mixer, the second intermediate-frequency filter and the second intermediate frequency amplifier, described the first frequency mixer is connected with the first local oscillator, and described the second frequency mixer is connected with the second local oscillator; Described the first frequency mixer upconverts to 30MHz～80MHz by described the first local oscillator by required radiofrequency signal, and by entering described the first intermediate frequency amplifier after described the first intermediate-frequency filter filtering; Described the second frequency mixer upconverts to 440KHz by described the second local oscillator by required radiofrequency signal, and by after described the second intermediate-frequency filter filtering, entering described the second intermediate frequency amplifier.
Described digital signal processing module comprises A-D converter and fpga core plate, and described A-D converter completes the data sampling of intermediate frequency 440KHz signal, and analog signal is transformed to the input of numeric field as described fpga core plate; Described fpga core plate has been used for the digital demodulation function of weather facsimile signals.
Described display control module comprises ARM core board, keyboard and liquid crystal display, the view data that described ARM core board is sent described fpga core plate here is stored with picture format, time, date and time information are added on described picture, and realize picture amplification, dwindle, move, spinfunction and picture is managed and retrieves; Described keyboard is positioned at the edge of described liquid crystal display, corresponding with the software interface shown on described liquid crystal display, by programming, realizes the difference in functionality under different interfaces; Described liquid crystal display is for showing weather facsimile figure and software interface.
Described display control module also comprises USB interface, and described USB interface is controlled by described ARM core board.
Described display control module also comprises buzzer, and described buzzer is controlled by described ARM core board.
Technique effect of the present utility model is: the utility model adopts digital demodulation techniques to convert the weather information of reception to digital signal, and is stored, shows, precision is high, antijamming capability is strong, cost is low; Adopt high intermediate frequency scheme, greatly improved intermediate frequency rejection ratio and the channel selectivity of facsimile machine; Adopt man-machine communication's mode, improved performance accuracy.
The accompanying drawing explanation
Fig. 1 is structural principle block diagram of the present utility model.
Fig. 2 is schematic appearance of the present utility model.
Fig. 3 is the digital demodulation signal flow chart in the utility model.
The workflow diagram that Fig. 4 is the display control module in the utility model.
Embodiment
Below in conjunction with accompanying drawing, embodiment of the present utility model is further described.
In Fig. 1, Fig. 2, comprise low noise amplifier 1, tunable preselection filter group 2, variable gain amplifier 3, the first frequency mixer 4, the first local oscillator 5, the first intermediate-frequency filter 6, the first intermediate frequency amplifier 7, the second frequency mixer 8, the second local oscillator 9, the second intermediate-frequency filter 10, the second intermediate frequency amplifier 11, A-D converter 12, fpga core plate 13, ARM core board 14, keyboard 15, liquid crystal display 16, usb 17, buzzer 18 etc.
As shown in Figure 1, the utility model is a kind of digital meteorology facsimile machine, comprise RF front-end module, digital signal processing module and display control module, RF front-end module has been used for the transformation of radiofrequency signal to intermediate-freuqncy signal, digital signal processing module has been used for the digital demodulation of intermediate-freuqncy signal, and display control module is for showing weather facsimile figure and the input control of reception.
RF front-end module comprises connected successively low noise amplifier 1, tunable preselection filter group 2, variable gain amplifier 3, the first frequency mixer 4, the first intermediate-frequency filter 6, the first intermediate frequency amplifier 7, the second frequency mixer 8, the second intermediate-frequency filter 10 and the second intermediate frequency amplifier 11, the first frequency mixer 4 is connected with the first local oscillator 5, and the second frequency mixer 8 is connected with the second local oscillator 9.
Tunable preselection filter group 2 is comprised of four groups of band pass filters, and band pass filter carries out gating by the control signal of fpga core plate 13 outputs.The first frequency mixer 4 is up-conversion mixer, by the first local oscillator 5, required radiofrequency signal is upconverted to 30MHz～80MHz, and, by entering the first intermediate frequency amplifier 7 after the first intermediate-frequency filter 6 filtering, form high intermediate frequency scheme, improved the intermediate frequency rejection ratio of system.The second frequency mixer 8 is down-conversion mixer, by the second local oscillator 9, required radiofrequency signal is upconverted to 440KHz, and, by entering the second intermediate frequency amplifier 11 after the second intermediate-frequency filter 10 filtering, this signal is as the input of digital signal processing module.
Digital signal processing module comprises A-D converter 12 and fpga core plate 13.A-D converter 12 completes the data sampling of intermediate frequency 440KHz signal, and analog signal is transformed to the input of numeric field as fpga core plate 13.Fpga core plate 13 is core processing units of the present utility model, on fpga core plate 13, power control circuit, FPGA minimum system and storage chip, consists of, for completing the digital demodulation function of weather facsimile signals.
Display control module comprises ARM core board 14, keyboard 15 and liquid crystal display 16.
ARM core board 14 is control unit, ARM9 chip, power circuit and storage chip, consists of, wherein the embedded (SuSE) Linux OS of ARM9 chip.ARM core board 14 is realized following functions: the view data that fpga core plate 13 is sent here is kept in the form into BMP, and is that the JPG picture format is stored by the BMP format conversion; Picture is added on time, date and time information on picture before preserving; Can realize picture amplification, dwindle, move, spinfunction; Can manage and retrieve picture.
As shown in Figure 2, keyboard 15 is positioned at the edge of liquid crystal display 16, corresponding with the software interface shown on liquid crystal display 16, by programming, realizes the difference in functionality under different interfaces.Keyboard 15 is silica gel push-button, generally comprises 5 programmable key F1, F2, F3, F4 and F5.
General 15 cun technical grade liquid crystal display screen displays, the weather facsimile figure and the software interface that receive or receiving for demonstration of adopting of liquid crystal display 16.
Display control module also comprises usb 17 and buzzer 18, and usb 17 and buzzer 18 are controlled by ARM core board 14 respectively.Usb 17 can connect printer and the USB flash disk that uses USB interface, can select to print required weather facsimile figure or the weather facsimile figure received is admitted to USB flash disk and be shifted.Buzzer 18 is for sending the prompt tone corresponding to various operations.
Operation principle of the present utility model is as follows: the utility model adopts the digital intermediate frequency scheme.RF front-end module is moved intermediate frequency (440KHz) by signal spectrum; High speed analog-to-digital converter 12 with 8M sample rate is converted to this intermediate-freuqncy signal digital medium-frequency signal and sends it to fpga core plate 13; In fpga core plate 13, digital medium-frequency signal experience Digital Down Converter Module becomes the baseband I Q two paths of signals that sample rate is 80KHz.In Digital Down Converter Module, the frequency deviation information that Direct Digital sequencer (DDS) is controlled by the output of remote control signal detection module sends the multiple intercarrier signal under the 8MHz sample rate; Multiply each other and obtain the CPFSK base band 1Q two paths of signals the 8MHz sample rate with this multiple intercarrier signal from the digital medium-frequency signal of A-D converter 12 outputs.
Digital demodulation signal is realized by programmable logic device fpga core plate 13, completes digital filtering, down-conversion, fsk signal demodulation and radio-frequency front-end and controls function.The digital demodulation signal flow process is as shown in Figure 3: after selected channel, at first detect initial signal, if the initial signal success detected, continue the detected phase signal, otherwise continue to wait for; After if phase signal being detected, to also determining mutually, transmission rate if do not return, detect initial signal; At first to detect line synchronizing signal before receiving picture signal, if detect successfully, receive data line, if detect unsuccessfully, detect whether end signal is arranged; Receive a line view data and judge whether that a line receives, if it is continue the check row synchronizing signal, if not continuing reception; Enter the link that detects end signal, no matter success or not, finish this chapter image and receive.
The workflow of display control module is as shown in Figure 4: the gui interface application program occurs for waiting event, in the state of continuous scanning, detect the presented event that whether changes, need the printing event, need the storage event, incoming event and UART communication event.If the change presented event detected, call LCD and drive; Need the printing event if detect, call USB and print driving; Need the storage event if detect, call SD and drive; If incoming event detected, enter the incoming event processing module, call keyboard drive and obtain key assignments and return to key assignments to the incoming event processing module, finally by the incoming event processing module, key assignments is delivered to the gui interface application program; If the UART communication event detected, enter the communication module with FPGA, the frame format that FPGA is transmitted is resolved, judgement is data message or image information, carry out Data Format Transform and data are sent into to the gui interface application program if data message enters data processing module, if control information enters the command analysis processing module, analyzed and control signal is sent into to the gui interface application program.
The key technology that the utility model is used has:
1, the variable CIC of reduce sampling frequency is down-sampled
The weather facsimile signals code check comprises 160/22KHz (IOC=576, RPM=240), 80/22KHz (IOC=576, RPM=120 or IOC=288, RPM=240), 60/22KHz (IOC=576, RPM=90), 40/22KHz (IOC=576, RPM=60 or (IOC=288, RPM=120), 30/22KHz (IOC=288, RPM=90), six kinds of situations of 20/22KHz (IOC=288, RPM=60).In order to facilitate subsequent treatment, the utility model is reduced to the sample rate of the CPFSK base band 1Q two paths of signals of 8MHz sample rate according to the IOC, the RPM parameter that receive picture 22 times of phase code rate, i.e. 160KHz, 80KHz, 60KHz, 40KHz, 30KHz, 20KHz.This process is completed by a variable CIC decimator of reduce sampling frequency.In the CIC decimator, data have experienced the level Four sample rate and have changed, and the first order is 5 times of CIC decimators, and the second level is 5 times of CIC decimators, the third level is that 3 times of CIC rise sampler, and the fourth stage is the CIC decimator that reduce sampling frequency can change between 3/6/8/12/16/24.The 4th grade of reduce sampling frequency variable C IC decimator consists of 5 grades of integrators, several sampler, 5 grades of difference engines, and the sampling multiple of sampler wherein is variable.Being exported to CPFSK signal demodulation module and remote control signal after the base band FIR filter that is 1200Hz through bandwidth through the low sampling rate IQ two paths of signals after the CIC decimator detects and channel estimation module.
2, the simplification sequence demodulation method of CPFSK signal
When a code element of judgement, the utility model is under the control of the lock-out pulse of remote control signal detection module output, intercept the sampling point of the baseband I Q two paths of signals that 66 above sample rates are 22 times of code checks, wherein first 22 is the interior baseband signal sampling point of i-1 symbol time, middle 22 sampling points are the baseband signal sampling point in i symbol time, and rear 22 sampling points are the baseband signal sampling point in i+1 symbol time.
66 plural sampling point data sequences of note intercepting are Si.In this sequential detector, Si and 000,001,010,011,100,101,110,111 8 kind of possible sequence data carry out relevant, get the intermediate symbol value of sequence of correlated results maximum as the decision value of i code element.After the judgement that completes a code element, this decision value is flowed to image and process and output module, move a symbol time (22 sampling points) after the window of simultaneously peeking.
3, the detect and recovery of symbol timing information and signal frequency deviation information
The phasing signal of meteorological chart is periodicity black and white alternating signal, and 5% white signal first appears in per cycle, and at the black signal that occurs 95%, the cycle is the row repetition period.The utility model carries out cross-correlation calculation by the method that adopts matched filtering to signal, and when correlation is greater than the certain proportion of average power signal, phasing signal has appearred in judgement.
Detect to walk abreast with phasing signal and carrying out a mixing operation, multiply each other by 2300Hz complex signal and data.The result multiplied each other is admitted to digital frequency discriminator, when phasing signal appears in judgement, flows to Digital Down Convert using frequency discriminator output as frequency deviation value in order to make it frequency deviation impact removal.From judgement, moment of phasing signal appears, according to the commutator pulse of the generation each row of data of signal code check and local timing cycle and give demodulation module in order to correct data intercept sampling point.
4, the detection method of the initial signal of meteorological chart, end signal
The utility model is monitored signal in FPGA, and signal is inputted to phase discriminator, and frequency detecting is carried out in output to phase discriminator.When the 300Hz of the frequency change track that monitors signal or 675Hz signal component energy are greater than the certain proportion of gross energy, the image initial signal has appearred in judgement, and change according to the frequency size IOC register value of exporting to variable bit rate CIC decimator, when 300Hz occurring, IOC is become to 576, when 675Hz occurring, IOC is become to 288.When the 450Hz signal component energy of the frequency change track that monitors signal is greater than the certain proportion of gross energy, the image end signal has appearred in judgement.When commencing signal occurring, the sequence of symhols of demodulator output to be arranged according to image, every row image pixel is 1818 points when IOC=576, when IOC=288, is 909 points.When end signal occurring, will finish synthetic image and generated image be stored.
The utlity model has following advantage:
1, the superheterodyne receiver structure is combined with the digital intermediate frequency demodulation scheme, both retained the advantage that the superhet short-wave receiver is highly sensitive, selectivity is good, introduced again digital demodulation techniques, adopt the modern signal processing algorithm to complete filtering and the signal demodulation of numeric field, overcome the nonlinear impairments of analog demodulator and the analog circuit precision is low, to shaking the shortcomings such as sensitivity, poor anti jamming capability;
2, adopt high intermediate frequency scheme, the first intermediate frequency is arranged on to 30MHz～80MHz (tradition is 10MHz), greatly improved intermediate frequency rejection ratio and the channel selectivity of facsimile machine;
3, provide the most direct a kind of man-machine communication's mode, do not needed loaded down with trivial details text maninulation explanation, and improved performance accuracy, greatly reduced the probability of operator error operation;
4, based on Embedded Software Design, a kind of style of opening, extendible hardware platform are provided, receive frequency, demodulation mode and key panel all can reconfigure by software, make this weather map facsimile equipment and new, old system compatibility, have extended life cycle;
5, the facsimile weather chart received is directly shown by liquid crystal display 16, and by data typing internal memory, be convenient to the management of image, can realize the query and search of meteorological chart, use external printer selective dump output, and can do preliminary treatment to image before printing, as operations such as noise reduction, phase corrections, avoid so invalid printout, saved resource;
6, configurable laser printer, overcome the shortcoming that the facsimile chart of thermal printing mode can not long preservation;
7, simple and compact for structure, cost is low.
Claims (6)
1. a digital meteorology facsimile machine, it is characterized in that: comprise RF front-end module, digital signal processing module and display control module, described RF front-end module has been used for the transformation of radiofrequency signal to intermediate-freuqncy signal, described digital signal processing module has been used for the digital demodulation of intermediate-freuqncy signal, and described display control module is for showing weather facsimile figure and the input control of reception.
2. according to digital meteorology facsimile machine claimed in claim 1, it is characterized in that: described RF front-end module comprises connected successively low noise amplifier (1), tunable preselection filter group (2), variable gain amplifier (3), the first frequency mixer (4), the first intermediate-frequency filter (6), the first intermediate frequency amplifier (7), the second frequency mixer (8), the second intermediate-frequency filter (10) and the second intermediate frequency amplifier (11), described the first frequency mixer (4) is connected with the first local oscillator (5), and described the second frequency mixer (8) is connected with the second local oscillator (9); Described the first frequency mixer (4) upconverts to 30MHz～80MHz by described the first local oscillator (5) by required radiofrequency signal, and by entering described the first intermediate frequency amplifier (7) after described the first intermediate-frequency filter (6) filtering; Described the second frequency mixer (8) upconverts to 440KHz by described the second local oscillator (9) by required radiofrequency signal, and by after described the second intermediate-frequency filter (10) filtering, entering described the second intermediate frequency amplifier (11).
3. according to digital meteorology facsimile machine claimed in claim 1, it is characterized in that: described digital signal processing module comprises A-D converter (12) and fpga core plate (13), described A-D converter (12) completes the data sampling of intermediate frequency 440KHz signal, and analog signal is transformed to the input of numeric field as described fpga core plate (13); Described fpga core plate (13) is for completing the digital demodulation function of weather facsimile signals.
4. according to digital meteorology facsimile machine claimed in claim 3, it is characterized in that: described display control module comprises ARM core board (14), keyboard (15) and liquid crystal display (16), the view data that described ARM core board (14) is sent described fpga core plate (13) here is stored with picture format, time, date and time information are added on described picture, and realize picture amplification, dwindle, move, spinfunction and picture is managed and retrieves; Described keyboard (15) is positioned at the edge of described liquid crystal display (16), corresponding with the upper software interface shown of described liquid crystal display (16), by programming, realizes the difference in functionality under different interfaces; Described liquid crystal display (16) is for showing weather facsimile figure and software interface.
5. according to digital meteorology facsimile machine claimed in claim 4, it is characterized in that: described display control module also comprises USB interface (17), and described USB interface (17) is controlled by described ARM core board (14).
6. according to digital meteorology facsimile machine claimed in claim 4, it is characterized in that: described display control module also comprises buzzer (18), and described buzzer (18) is controlled by described ARM core board (14).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320441947.7U CN203377950U (en) | 2013-07-24 | 2013-07-24 | Digital meteorological facsimile machine |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201320441947.7U CN203377950U (en) | 2013-07-24 | 2013-07-24 | Digital meteorological facsimile machine |
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| CN203377950U true CN203377950U (en) | 2014-01-01 |
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| CN201320441947.7U Expired - Fee Related CN203377950U (en) | 2013-07-24 | 2013-07-24 | Digital meteorological facsimile machine |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103428401A (en) * | 2013-07-24 | 2013-12-04 | 南京虹航电子科技有限公司 | Digital meteorologic fax machine |
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2013
- 2013-07-24 CN CN201320441947.7U patent/CN203377950U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103428401A (en) * | 2013-07-24 | 2013-12-04 | 南京虹航电子科技有限公司 | Digital meteorologic fax machine |
| CN103428401B (en) * | 2013-07-24 | 2016-06-29 | 南京海善达信息科技有限公司 | Digital meteorologic fax machine |
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Legal Events
| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20140101 Termination date: 20160724 |